Interpretive Summary: Parasitic wasps are important components in the biological control of agricultural crop pests, and many of these wasps attack pestiferous caterpillars that cause millions of dollars of losses annually in agricultural and horticultural systems worldwide. The moth family commonly known as slug caterpillars includes invasive pests that not only damage crops such as oil palm, coconut, and bananas, but also some species that have stinging hairs that cause contact dermatitis in humans. A new parasitic wasp is described that is a specialist parasite of slug caterpillars. It is compared to related species and illustrated. This information will aid biocontrol workers, scientists, and port inspectors working with slug caterpillars and their parasites.

Technical Abstract:
Alveoplectrus lilli Gates, new species, is described and illustrated. This species was reared from five genera of field-collected slug caterpillars (Lepidoptera: Limacodidae) in eastern North America. It is compared to closely related New World species. We report on new host records and summarize the biology of this species.